Physics and Dynamics Coupling Across Scales in the Next Generation CESM: Meeting the Challenge of High Resolution
Collaborative Institutional Lead(s):
We propose to reformulate the physics-dynamics coupling for the NCAR/DOE High-Order Method Modeling Environment (HOMME) a new dynamical core now available within the Community Earth System Model (CESM). We will utilize sub-grid information estimated directly from the HOMME numerics and from an advanced, probability-density-function based model of sub-grid variability. This will be coupled to model physics subroutines using a sub-column framework, in which ensembles of uniform sub-columns are generated by sampling from assumed sub-grid distributions of meteorological and microphysical quantities. This approach will allow physically based microphysics schemes to be used for CESM-HOMME climate simulations at a range of horizontal grid spacings without ad hoc tuning. In addition we will modify the dynamical equations in HOMME to account for the effects of precipitation mass on the dynamical pressure field – an effect that becomes important at high climate resolutions (i.e., (Δ, Δ)~10km).